1. Field of the Invention
The present device is directed generally to the packaging for an electronics module. More specifically, the present invention is directed to the architecture of the packaging that houses a single module, either a transmitter or a receiver, of a millimeter wave device.
2. Background Information
The main components in millimeter wave (MMW) transceivers are monolithic millimeter wave integrated circuit (MMIC) chips, connective substrates, housings, and DC regulators/controllers. It has traditionally been difficult to design and build very wideband amplifiers that display consistent performance across the entire passband. Gain irregularities and peaks, large variations of input and output impedance, and spurious oscillations are examples of the problems encountered.
Monolithic millimeter wave integrated circuit (MMIC) devices are low-cost solutions to the problems. The cost of MMIC chips and substrates have been steadily falling in the last few years due to improved yield and increased demand for commercial telecommunication applications. However, the two areas of housings and regulators/controllers have not enjoyed similar cost reductions because, for example, Coefficient of Thermal Expansion (CTE) matching and thermal conductivity requirements limit the material choices for packaging and make it difficult to reduce costs.
U.S. Pat. No. 4,490,721, issued to Stockton et al., the disclosure of which is hereby incorporated by reference, discloses the fabrication of MMIC components and their interconnects onto a single substrate by using thin film and IC fabrication techniques.
U.S. Pat. No. 5,945,941, issued to Rich, III et al., the disclosure of which is hereby incorporated by reference, discloses a pulsed radar apparatus and method for employing a power distribution system having reduced cost and weight and enhanced efficiency and reliability. The power distribution system is provided in a radar apparatus to distribute power from a 270 VDC source through an intermediate power converter and very high frequency (VHF) regulator/modulator units. Costs are reduced through the use of electrical components with increased efficiency.
U.S. Pat. No. 5,493,305, issued to Woodbridge et al., the disclosure of which is hereby incorporated by reference, discloses a vertical, multi-layer arrangement of MMIC chips to facilitate automated assembly and increase yields.
The present invention is directed to reducing the cost of MMW housings through the appropriate selection and application of materials. The cost of the regulator/controller can be reduced through the use of surface mount parts and simplified DC and RF interfaces. Exemplary embodiments provide a generic housing for MMW module assemblies that accommodate frequencies from 20 to 40 GHz without changing the design, thus improving the modularity.
An exemplary millimeter wave transceiver package in accordance with the present invention comprises a multilayered structure of planar housings stacked vertically. A cover to an electrical housing and a surface mount board is positioned at a first edge of the vertical stack. A surface mount board is positioned as a second layer. The third layer is an electrical housing made from aluminum and comprising a regulator/controller. The RF components are housed in a fourth layer made from copper tungsten. A plurality of interconnected channels are recessed into a planar surface of the housing, either by machining or by the joining of a channelized layer and flat base layer. Only MMIC chips and connective substrates are disposed in the plurality of channels. An RF cover made from Kovar is disposed at a second edge of the vertical stack and forms a seal over the MMIC chips and connective substrates.